User with permissions:

• Start Node is node beneath main content node.
• Sections: Only Content is checked
• User Type: Has all default permissions except "Manage hostnames", "Send To Publish", "Permissions", and "Translate"
• User Permissions : nothing here

User navigates to existing content page beneath "Start Node". RTE on content has existing link.  User selects link then clicks edit hyperlink in RTE (TinyMCE) toolbar.  New window opens with error page.

Error Received: 

At /umbraco/plugins/tinymce3/insertLink.aspx (Referred by: http://www.wec-cpa.com/umbraco/editContent.aspx?id=1588): System.ArgumentException: The current user doesn't have access to this application. Please contact the system administrator. at umbraco.controls.Tree.TreeControl.Initialize() at umbraco.controls.Tree.TreeControl.OnPreRender(EventArgs e) at System.Web.UI.Control.PreRenderRecursiveInternal() at System.Web.UI.Control.PreRenderRecursiveInternal() at System.Web.UI.Control.PreRenderRecursiveInternal() at System.Web.UI.Control.PreRenderRecursiveInternal() at System.Web.UI.Control.PreRenderRecursiveInternal() at System.Web.UI.Control.PreRenderRecursiveInternal() at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)

Need help with this ASAP.  This is on a production site